The present invention relates generally to fuzes, and more particularly to an improved joint for preventing the relative rotation of the base and cap of the fuze during static and dynamic conditions.
A major concern of fuze designers is to prevent the relative rotation of the base and cap of a fuze under the influence of angular acceleration force during firing. The fuzes of the prior art have generally included adjacent annular engaging surfaces perpendicular to the axis of rotation, said surfaces being substantially smooth. To prevent rotation of the members relative to each other during firing, the frictional engagement of the smooth surfaces has been increased. A typical example of a method to increase the frictional engagement of the rotational parts is illustrated in U.S. Pat. No. 2,216,862. A sinuous resilient band is positioned in mutually registered annular grooves in the adjacent surfaces. The band provides radial force sufficient to increase frictional engagement between the relatively movable parts.
When dealing with smooth engaging surfaces of the members of a fuze of the prior art, the friction inducing elements require a torque of approximately 150 inch-pounds or greater to rotate the members relative to each other to set the fuze in a static condition. Because of the smooth surfaces, this degree of torque is needed to reduce relative motion of the parts during firing. Thus, prior art fuzes are difficult to set and relative motion of the parts is not entirely eliminated during firing. Thus, there exists a need for a fuze joint which is capable of preventing relative movement of the two members of a fuze under the influence of angular acceleration during firing as well as requiring a minimum amount of torque to set the fuze under static conditions.